BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Vesper Sparrow In Northern Rockies

All regionsNorthern RockiesGrassland birds

Vesper Sparrow in Northern Rockies has risen sharply: up 61% on the route-weighted index since 1970.

+61%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
188Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Vesper Sparrow has risen sharply in Northern Rockies: up 61% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Vesper Sparrow in Northern Rockies is projected to fall about 10% by 2029 — from 19 in 2024 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±12.1%, with 80% of held-out values landing inside the 95% band.

-10%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
17Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
13–2295% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±12.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Vesper Sparrow in Northern Rockies is projected to fall about 10% by 2029 — from 19 in 2024 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±12.1%, with 80% of held-out values landing inside the 95% band.19682029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
2025171322
2026171322
2027171322
2028171322
2029171322

Routes In Northern Rockies

Routes recording Vesper Sparrow in Northern Rockies.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
PolsonMONTANA1312024
BairoilWYOMING1042024
BeaverheadMONTANA1012024
BoulderMONTANA1002024
Wolf CreekMONTANA882022
AugustaMONTANA862024
Saleratus CrUTAH862018
Freeman CreekMONTANA812016
Fort LoganMONTANA802024
LamontWYOMING762024
MeeteetseWYOMING722024
Heart ButteMONTANA702024
BaggsWYOMING662024
RyegrassWYOMING652024
Great DivideCOLORADO622024
Neponset ResUTAH612018
Seedskadee 2WYOMING612024
St. Mary 2MONTANA602024
St MaryMONTANA572008
Brunzell SloughMONTANA572024
BoulderWYOMING552024
Ne EntranceWYOMING502021
Muddy CreekMONTANA492015
Clyde ParkMONTANA462024
Willow CreekMONTANA441981

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.